Canister air filter and method for fabricating the same

ABSTRACT

Embodiments for a filter and method for fabricating the same are provide herein. In one embodiment, a filter is provided that includes a first end cap, a second end cap, at least a first filtration media element and at least a first brace. The first end cap has an air flow aperture formed therethrough. The first and second end caps define a central axis. The first filtration media element is coupled to the first and second end caps and has an orientation curved around the central axis. The brace separates a first closed edge of the filtration media element from a second closed edge of the filtration media element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The embodiments of the invention generally relate to a canister airfilter and methods for fabricating the same.

2. Description of the Related Art

Canister air filters may be employed for a variety of uses, includingindustrial dust collectors. In many dust collectors, the canister airfilter is mounted in a substantially horizontal orientation tofacilitate the removal and replacement of the filters once theoperational life of the filters has been exceeded. In a horizontalorientation, i.e., a filter orientation wherein the center line of thecanister air filter is substantially horizontal, the filtration mediaexposed at the top of the filter rapidly becomes coated with dust cakedue to gravity and air flow patterns within the dust collector. The dustcake prevents air from passing through the filtration media. Thus, thetop portion of the canister filter typically provides little or no airfiltration in comparison to the remainder of the filter duringsubstantial periods of normal operation. Some industrial dust collectorsutilize a reverse pulse of air to remove the dusk cake, but therelatively heavier dust cake present at the top relative to thesides/bottom of the canister filter may not be completely removed duringthe reverse pulse, leaving the top portion of the canister filter in apartially blocked state reducing the performance of the filter. Sincethe filtration media is one of the most expensive components of thecanister filter, the presence of partially blocked filtration media atthe top of the canister air filter adversely affects to the balancebetween material costs to filter performance.

Therefore, there is a need for an improved canister air filter.

SUMMARY OF THE INVENTION

Embodiments for a filter and method for fabricating the same areprovided herein. In one embodiment, a filter is provided that includes afirst end cap, a second end cap, at least a first filtration mediaelement and at least a first brace. The first end cap has an air flowaperture formed therethrough. The first and second end caps define acentral axis. The first filtration media element is coupled to the firstand second end caps and has an orientation curved around the centralaxis. The brace separates a first edge of the filtration media elementfrom a second edge of the filtration media element.

In another embodiment, a filter is provided that includes a first endcap, a second end cap, a first filtration media element, a secondfiltration media element, a first brace and a second brace. The firstend cap has an air flow aperture formed therethrough and faces thesecond end cap. The first and second filtration media elements have openedges sealingly engaged with the first and second end caps. The firstfiltration media element and the second filtration media element defineat least a portion of a tubular filtration media assembly. The firstbrace and the second brace are coupled to the first and second end caps.The first brace separates a first closed edge of the first filtrationmedia element from a first closed edge of the second filtration mediaelement. The second brace is sealed to a second closed edge of the firstfiltration media element.

In yet another embodiment, a method for fabricating a filter isprovided. In one embodiment, the method includes non-concentrically andnon-axially arranging open edges of at least a first filtration mediaelement and a second filtration media element to form a tubular sleeveof filtration media, adjacent closed edges the two filtration mediaelements separated by a brace, and sealing the open edges of the firstfiltration media element and the second filtration media element to forma canister filter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, schematically illustrate the presentinvention, and together with the general description given above and thedetailed description given below serve to explain the principles of theinvention.

FIG. 1 is an isometric view of one embodiment of a canister air filter;

FIG. 2 is an isometric view of one embodiment of a filtration media anda brace prior to forming a tubular filtration media assembly;

FIG. 3 is a partial elevation of the canister air filter of FIG. 1;

FIG. 4 is a sectional view of the air filter of FIG. 1 taken alongsection line 2-2;

FIG. 5 is a top view of the canister air filter of FIG. 1;

FIG. 6 is a bottom view of the canister air filter of FIG. 1;

FIG. 7 is a isometric view of another embodiment of a canister airfilter;

FIG. 8 is a cross-sectional view of the canister air filter of FIG. 7taken along section lines 8-8;

FIG. 9 is a top view of the canister air filter of FIG. 7;

FIG. 10 is a bottom view of the canister air filter of FIG. 7; and

FIG. 11 is a flow diagram for one embodiment of a method for fabricatinga canister air filter.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements of one embodiment may bebeneficially incorporated in other embodiments without furtherrecitation.

It is to be noted, however, that the appended drawings illustrate onlyexemplary embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

DETAILED DESCRIPTION

FIGS. 1-2 are isometric and sectional views of one embodiment of acanister filter 100. Referring to both FIGS. 1-2, the canister filter100 generally has a tubular orientation centered on a central axis 122.In one embodiment, the canister filter 100 includes a first end cap 102,a second end cap 104, at least a first media element 106 and at least afirst brace 108. An optional outer screen 114 may cover the first mediaelement 110, and is shown cut away in FIG. 1, to reveal the first mediaelement 110. The first and second end caps 102, 104 generally define thedistal ends of the canister filter 100 and generally have an orientationsubstantially perpendicular to the center line 122. It is alsocontemplated that the first and second end caps 102, 104 mayalternatively have an orientation non-perpendicular to the center line122.

Generally, the number of media elements equals the number of braces. Forexample, the canister filter 100 may include N media elements and Nbraces, wherein N is an integer greater than or equal to 1. The N mediaelements and N braces form tubular filtration media assembly 124. Thedistal ends of the N media elements and N braces are sealed to the endcaps 102, 104. In the embodiment depicted in FIGS. 1-6, the first mediaelement 106 and the first brace 108 form the tubular filtration mediaassembly 124.

The profile of the tubular filtration media assembly 124 is illustratedwith greater clarity in the sectional view of the canister filter 100depicted in FIG. 4. Although the tubular filtration media assembly 124is illustrated in FIG. 4 as a circle having internal volume, the tubularfiltration media assembly 124 may be configured to have other sectionalprofiles, such as oval, elliptical, polygonal or other tubular shape.

Referring back to both FIG. 1 and FIG. 2, the first filter element 106includes filtration media 110. The filtration media 110 may be in theform of particulate or molecular phase filtration media. In oneembodiment, suitable filtration media includes carbon containingfiltration media, carbon-based filtration media, carbon filtrationmedia, high loft filtration media, cellulous filtration media, wet laidfilter media, glass filtration media, polymeric filtration media orother suitable filtration media. In one embodiment, the filtration media110 may be pleated to increase the effective surface area of the firstmedia element 106. The pleats of the filtration media 110 may be securedin a pre-defined orientation by a separator 112. The separator 112 maybe in the form of a continuous or discontinuous adhesive or hot melt, astring separator, a rigid separator or other pleat spacing element.

When pleated, the first media element 106 includes open edges 202, 204and closed edges 206, 208. The open edges 202, 204 of the filtrationmedia 110 define the edges of the filtration media 110 perpendicular tofolds 210 of the pleats while the closed edges 206, 208 of thefiltration media 110 define the edges of the filtration media 110parallel to the folds 210 of the pleats. To fabricate the tubularfiltration media assembly 124 (not shown assembled in FIG. 2), anadhesive 212 is utilized to secure the first closed edge 206 of thefiltration media 110 to a first lateral side 214 of the first brace 108.The second closed edge 208 of the filtration media 110 is doubled backand secured, for example, by additional adhesive 212, to a secondlateral side 216 of the first brace 108 to form the tubular filtrationmedia assembly 124, as shown along phantom arrows 218.

In embodiments wherein N media elements and N braces are used form thetubular filtration media assembly 124, the first closed edge of theN^(th) media element is secured to the first side of the N^(th) brace.The first closed edge of the N^(th)−1 media element is secured to thesecond side of the N^(th) brace. The second closed edge of the N^(th)−1media element is secured to the first side of the N^(th)−1 brace. TheN^(th)−1 brace is secured to the second closed edge of the N^(th) mediaelement, or to one or more additional brace and media element pairs intothe tubular assembly is formed 124.

The adhesive 212 or alternative technique utilized to secure the closededges 206, 208 of the filtration media 110 to the first brace 108 isselected to substantially prevent air leakage. Generally, the sealingadhesive 212 and/or technique may be selected commensurate with thelevel of leakage permissible for the application for which the canisterfilter 100 is intended for use. In one embodiment, the adhesive 212and/or sealing technique provides a substantially air tight seal atpressure drops across the media element 106 up to at least about 6inches water gage. In the embodiment depicted in FIG. 2, the adhesive212 utilized to secure the closed edges 206, 208 of the filtration media110 to the first brace 108 may include tape, pressure sensitiveadhesives, polyurethane adhesives, epoxy, latex adhesives, hot melt orother suitable adhesive compound.

The open edges 202, 204 of the filtration media 110 and opposite ends132, 134 of the first brace 108 are sealed to the end caps 102, 104. Theopen edges 202, 204 and ends 132, 134 may be sealed by any suitablemanner. In the embodiment depicted in the partial elevation of FIG. 3having the outer screen 114 removed, the first open edge 202 of thefiltration media 110 and the end 132 of the first brace 108 are pottedin, molded or otherwise adhered to the end cap 102, as shown in phantom,thereby substantially preventing air leakage around the open edge 204 ofthe folds 210 of the pleats. In one embodiment, the first end cap 102 iscasted from polyurethane, ceramic or other suitable polymer.Alternatively, the first end cap 102 may be in the form of an annulardisk for retaining a compound in with the first open edge 202 of thefiltration media 110 and the end 132 of the first brace 108 may beengaged and sealed. The second open edge 204 of the filtration media 110and the second end 134 of the first brace 108 are similarly sealed tothe second end cap 104.

The first brace 108 provides one or more functions. The canister filter100 may be installed in an orientation having the first brace 108exposed on the top of the filter, thereby preventing vertically fallingparticulates from clogging upward facing filtration media of thecanister filter 100. Additionally, as the first brace 108 is astructural member spanning between the end caps 102, 104, the firstbrace 108 allows greater compression forces to be exerted on thecanister filter 100 without fear of collapse, thereby allowing higherand generally more effective sealing forces to be utilized to secure thecanister filter 100 in a dust collector or other filter holding device.

Referring now back to FIG. 1 and the sectional view of FIG. 4, the firstbrace 108 may be fabricated from a substantially rigid material, such asaluminum, plastic, wood or paper product or other suitable material. Inone embodiment, the first brace 108 is an extrusion. The first brace 108may include a hollow to increase rigidity while decreasing cost. It isalso contemplated that the first brace 108 may be stamped or vacuumformed.

The first brace 108 includes an outer surface 404 and an inner surface406 that are sandwiched between the lateral sides 214, 216. The outersurface 404 may have a radius having an origin on the central axis 122.The inner surface 406 may also have a radius having an origin on thecentral axis 122. The inner surface 406 may optionally have a radiushaving an origin defined between the central axis 122 and the innersurface 406. The inner surface 406 may optionally have a radius greaterthan that of the outer surface 404.

The first brace 108 includes outer lips 420 adjacent the outer surface404 and inner lips 422 adjacent the inner surface 406. The lips 420, 422extend beyond the lateral sides 214, 216 to define respective troughs424, 426. The troughs 424, 426 receive the closed edges 206, 208 of thefiltration media 110. The outer lips 420 also secure the ends of theouter screen 114 in the troughs 424, 426 while the inner lips 422 secureends of an optional inner screen 402 in the troughs 424, 426.

The outer screen 114 protects the filtration media 110 from damage andmay be fabricated from a metal, plastic or other suitable material. Theouter screen 114 may be an expanded material, a perforated sheet, amesh, a web or other suitable air permeable material. The optional innerscreen 402 may be similarly constructed. The screens 114, 402 may bepotted in the end caps 102, 104 with the filtration media 110 and thefirst brace 108.

At least one of the end caps 102, 104 has an aperture that allows air toenter into or flow out of an interior 440 of the canister filter 100,depending on the direction of air flow though the first media element106. In the embodiment depicted in FIG. 1, and as more clearlyillustrated in the plan view of FIG. 5, the first end cap 102 includesan aperture 118 formed therethrough. The aperture 118 may becircumscribed by a boss 120, thereby allowing the canister filter 100 tobe more precisely positioned in a mating receiving element. The boss 120also allows location of a seal 116 on the first end cap 102. The seal116 may be a gasket, o-ring, pour-in-place elastomer or other suitablesealing member. In one embodiment, the seal 116 is an elastomer securedto the first end cap 102 by a pressure sensitive adhesive.

The second end cap 104 may be solid or include an optional an aperturethat allows air to enter into or flow out of the interior volume 440 ofthe canister filter 100. In the embodiment depicted in the bottom viewof the canister filter 100 of FIG. 6, the optional aperture 602 is shownin phantom.

In one mode of operation, air to be filtered is provided to the outsideof the canister filter 100. Air passes through the filtration media 110and into the interior volume 240. The filtered air in the interiorvolume 240 exits the canister filter 100 through the aperture 118 formedin the end cap 102. In another mode of operation, the air to be filteredis provided to the interior volume 240 of the canister filter 100through the aperture 118 formed in the end cap 102. The air is filteredas the air passes through the filtration media 110 to the exterior ofthe canister filter 100.

FIGS. 7-8 are isometric and sectional views of one embodiment of acanister filter 700. Referring to both FIGS. 7-8, the filter 700 isgenerally similar to the canister filter 100 described above, centeredon a central axis 722. In one embodiment, the filter 700 includes afirst end cap 702, a second end cap 704 and a tubular media assembly760. The tubular media assembly 760 includes a plurality of mediaelements and a plurality of braces which are coupled together to form atube as discussed above. In the embodiment depicted in FIGS. 7-8, thetubular media assembly 760 includes a first media element 870 and asecond media element 872 interleaved with a first brace 874 and a secondbrace 876. It is contemplated that the tubular media assembly 760 mayinclude more than two media elements and braces, for example, thetubular media assembly 760 may include the N media elements and Nbraces, wherein N is an integer greater than or equal to 3. The tubularmedia assembly 760 may have a circular or non-circular section asdiscussed above.

The canister filter 700 may also include optional outer and innerscreens 714, 814. The outer and inner screens 714, 814 may be fabricatedfrom an expanded material, a perforated sheet, a mesh, a web or othersuitable air permeable material. The screens 714, 814 may be potted inthe end caps 702, 704 with the tubular media assembly 760 as describedabove.

Referring primarily to the sectional view of FIG. 8, the first brace 874may be fabricated from a substantially rigid material, such as aluminum,plastic, wood or paper product or other suitable material. The firstbrace 874 may be extruded, stamped, vacuum formed or fabricated byanother suitable method. The first brace 874 may include a hollow toincrease strength and decrease cost.

In one embodiment, the first brace 874 includes an outer surface 802, aninner surface 804, a first lateral side 806 and a second lateral side808. The outer surface 802 of the first brace 874 may have a radiushaving an origin on the central axis 722. The inner surface 804 may alsohave a radius having an origin on the central axis 722. The innersurface 804 may optionally have a radius less, equal to or greater thana radius of the outer surface 802. In the embodiment depicted in FIG. 8,the radius of the inner surface 804 has an origin between the centeraxis 722 and the inner surface 804.

In one embodiment, the first brace 874 may include outer lips 820adjacent the outer surface 802 and inner lips 822 adjacent the innersurface 804. The lips 820, 822 extend beyond the lateral sides 806, 808to define respective troughs 824, 826. The troughs 824, 826 receive theclosed edges of the adjacent filtration media utilized to form thetubular media assembly 760. The closed edges of the filtration media maybe sealed to the first brace 874 as described above. The outer lips 820also secure ends of the outer screen 714 in the troughs 824, 826 whilethe inner lips 822 secure ends of the optional inner screen 814 in thetroughs 824, 826.

The second brace 876 is separated from the first brace 874 by the firstmedia element 870 and the second media element 872. In one embodiment,the first media element 870 and the second media element 872 aresubstantially equal in length, such that the second brace 876 positioned180 degrees from the first brace 874. Alternatively, the second brace876 may be positioned closer to one side of the first brace 874.

The second brace 876 may be fabricated as described above with referenceto the first brace 874. The sectional profile of the second brace 876may be identical to or different than the first brace 874. In oneembodiment, the second brace 876 has a smaller sectional profile thanthe first brace 874 as to minimized the area taken by the braces,thereby allowing for more of the circumference of the canister filter700 to be utilized for filtration media. In the embodiment depicted inFIG. 8, the second brace 876 is a smaller mirror image of the firstbrace 874. The use of multiple braces allows for increase filterrigidity and increased options for mounting the canister filter 700 todust collection mechanisms or other filter holding device.

In one embodiment, the second brace 876 includes an outer surface 852,an inner surface 854, a first lateral side 856 and a second lateral side858. The outer surface 852 of the second brace 876 may have a radiushaving an origin on the central axis 722, and in one embodiment, has aradius equal to that of the outer surface 802 of the first brace 874.The inner surface 854 may also have a radius having an origin on thecentral axis 722. The inner surface 854 may optionally have a radiusless, equal to or greater than a radius of the outer surface 852. In theembodiment depicted in FIG. 8, the radius of the inner surface 854 hasan origin between the center axis 722 and the inner surface 854, and hasa radius greater than that of the inner surface 804 of the first brace874.

In one embodiment, the second brace 876 may include outer lips 860adjacent the outer surface 852 and inner lips 862 adjacent the innersurface 854. The lips 860, 862 extend beyond the lateral sides 856, 858to define respective troughs 864, 866. The troughs 864, 866 receive theclosed edges of the adjacent filtration media utilized to form thetubular media assembly 760. The closed edges of the filtration media maybe sealed to the second brace 876 as described above. The outer lips 860also secure ends of the outer screen 714 in the troughs 864, 866 whilethe inner lips 862 secure ends of the optional inner screen 814 in thetroughs 864, 866.

At least one of the end caps 702, 704 has an aperture that allows air toenter into or flow out of an interior volume 844 of the canister filter700, depending on the direction of flow though the tubular mediaassembly 706. In the embodiment depicted in FIG. 7, and as more clearlyillustrated in the plan view of FIG. 9, the first end cap 702 includesan aperture 718 formed therethrough. The aperture 718 may becircumscribed by a boss 720, thereby allowing the canister filter 700 tobe more precisely positioned in a mating receiving element. The boss 720also allows location of a seal 716 on the first end cap 702. The seal716 may be a gasket, o-ring, pour-in-place elastomer or other suitablesealing member. In one embodiment, the seal 716 is an elastomer securedto the first end cap 702 by a pressure sensitive adhesive.

The aperture 718 may have a circular or other shape. In the embodimentof FIG. 9, the aperture 718 includes a central circular portion 902 andtwo truncated wedge portions 904, 906 that forms a butterfly shape. Thewedge 904 may be larger than the wedge 906.

The second end cap 704 may be solid or include an optional an aperturethat allows air to enter flow into or out of an interior 840 of thecanister filter 700. In the embodiment depicted in the bottom view ofthe canister filter 700 of FIG. 10, the optional aperture 1002 is shownin phantom.

FIG. 11 is a flow diagram of one embodiment of a method 1100 forfabricating a canister filter. The method 1100 begins at step 1102 byforming a tubular media assembly comprising at least one brace and atleast one filtration media element. The at least one brace and at leastone filtration media element are arranged to form a sleeve, i.e.,arranged in a non-axial and non-concentric orientation. The tubularmedia assembly is formed by sealingly coupling the filtration mediaelement (s) to the brace(s). The tubular media assembly may optionallyinclude an inner and/or outer screen. At step 1104, the tubular mediaassembly is sealed to opposing end caps. In one embodiment wherein thetubular media assembly includes pleated filter media, the open edges ofthe pleated filter media and the ends of the brace(s) are potted in orotherwise sealed to opposing end caps.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A filter comprising: a first end cap having an air flow apertureformed therethrough; a second end cap facing the first end cap, thefirst end cap and the second end cap defining a central axis; at least afirst filtration media element having a first open edge sealinglyengaged with the first end cap and a second open edge sealingly engagedwith the second end cap, the first filtration media element having anorientation curved relative to the central axis; and at least a firstbrace coupled to the first end cap and the second end cap, the firstbrace separating a first closed edge of the first filtration mediaelement from a second closed edge of the first filtration media element.2. The filter of claim 1, wherein the first filtration media element ispleated.
 3. The filter of claim 1, wherein the first filtration mediaelement is a molecular phase filtration media.
 4. The filter of claim 3,wherein the molecular phase filtration media further comprisecarbon-based media.
 5. The filter of claim 1, wherein the first bracefurther comprises: an extruded or stamped member.
 6. The filter of claim1, wherein the first brace further comprises: a hollow interior.
 7. Thefilter of claim 1, wherein the first brace further comprises: aninterior wall facing the central axis; an exterior wall facing away fromthe interior wall; and side walls extending between the interior walland the exterior wall, wherein the first closed edge of the firstfiltration media element is sealed to one of the side walls.
 8. Thefilter of claim 7, wherein the exterior wall has a radius having anorigin at the central axis.
 9. The filter of claim 1, wherein the firstclosed edge of the first filtration media element is sealed to the firstbrace.
 10. The filter of claim 1 further comprising: a second bracecoupled to the first end cap and the second end cap, wherein the firstclosed edge of the first filtration media element is sealed to the firstbrace and the second closed edge of the first filtration media elementis sealed to the second brace.
 11. A filter comprising: a first end caphaving an air flow aperture formed therethrough; a second end cap facingthe first end cap; a first filtration media element having open edgessealingly engaged with the first end cap and the second end cap; asecond filtration media element having open edges sealingly engaged withthe first end cap and the second end cap, the first filtration mediaelement and the second filtration media element defining at least aportion of a tubular filtration media assembly; a first brace coupled tothe first end cap and the second end cap, the first brace separating afirst closed edge of the first filtration media element from a firstclosed edge of the second filtration media element; and a second bracecoupled to the first and second end caps, the second brace sealed to asecond closed edge of the first filtration media element.
 12. The filterof claim 11, wherein the first filtration media element and the secondfiltration media element are pleated.
 13. The filter of claim 11,wherein the first filtration media element and the second filtrationmedia element comprises molecular phase filtration media.
 14. The filterof claim 11, wherein the first brace further comprises: an extruded orstamped member.
 15. The filter of claim 11 further comprising: an innerscreen disposed inward of the first filtration media and the secondfiltration media element.
 16. The filter of claim 11, wherein thetubular filtration media assembly is at least one of an oval, cylinderor polygon.
 17. The filter of claim 11, wherein the first closed edge ofthe first filtration media is sealed to the first brace.
 18. The filterof claim 11, wherein the first brace is sealed to the first closed edgeof the first filtration media element and to the first closed edge ofthe second filtration media element; and wherein the second brace issealed to a second closed edge of the second filtration media element.19. A method for fabricating an air filter, the method comprising:non-concentrically and non-axially arranging open edges of at least afirst filtration media element and a second filtration media element toform a tubular sleeve of filtration media, adjacent closed edges thefirst filtration media element and the second filtration media elementseparated by a brace; sealing adjacent closed edges of the first andsecond filtration media elements to the brace; and sealing the openedges of the first filtration media element and the second filtrationmedia element to form a canister filter.
 20. A method for fabricating anair filter, the method comprising: non-concentrically and non-axiallyarranging open edges of at least a first filtration media element toform a tubular sleeve of filtration media, adjacent closed edges of thefirst filtration media element separated by a brace; sealing adjacentclosed edges of the first filtration media element to the brace; andsealing the open edges of the first filtration media element to form acanister filter.